This project develops, analyses, and tests neural network leaky accumulator/drift diffusion models of decision-making, perceptual choice, memory recall, and attention. The Center hypotheses will be operationalized in these models, and then numerical simulations and analytical methods of dynamical systems theory will be used to study the models, predict their behavior, and delineate parameter ranges that provide optional behaviors, and that best correspond to empirical data. Such models formalize and sharpen the major Center hypotheses, complementing the experimental work of Projects 1-5. The project will also work to connect these 'high level'models to biophysically-based models of heterogeneous neural pools. Success in this effort will lead to a more precise understanding of the mechanisms that govern the execution of cognitive tasks and their neural implementation.